What does it all depend on and what to do
Starter bikes are equipped with the cheapest transmissions, and the gears on them are poorly shifted and jammed. An experienced cyclist will quickly be able to determine the level of the drivetrain. The point is that its disordered work is not always associated with the class, but more depends on the setting and state. Let’s try to list most of the factors causing such problems.
It must be understood that the speed changes only when the chain moves forward. If you jerked the shifter, then you need to rotate the pedal so that the chain spreads from one star to another. If, when switching, clicking or any other extraneous sounds are emitted, you need to adjust the switching.
The main reasons for inaccurate switching:
- The transfer cable is torn, stretched, or is on the verge of breaking.
- The switch itself is broken or the spring in it is worn out.
- The teeth of the rollers are worn down.
- Switch needs to be adjusted.
- The chain or cassette is worn out.
- A lot of dirt got into the chain.
Rear derailleur play
Move the rear derailleur towards you and away from you, keeping where the cable goes. Ideally, there should be no backlash at all, but a small free play does not represent anything criminal, especially on the initial transmission groups.
During operation, this backlash tends to increase, and then delays in switching, fuzziness, etc. begin. If everything is in order with the cables and the rooster, then with fine tuning you can overcome the negative effect of backlash.
To prevent damage, you need to be able to switch gears correctly.
Deformed rear derailleur bracket
There are times when a seemingly perfectly tuned rear derailleur malfunctions despite new cables and shirts. The reason may be that the bike was caught somewhere during transport, and the bracket bent a little. If it is not possible to establish a clear gear shifting, then it is worth removing the cock and putting it on the table. Crooked? You need to fix it. But it’s important not to overdo it, as aluminum cracks.
It sometimes happens that a seemingly perfectly tuned rear derailleur doesn’t work well despite fresh cables and shirts. The reason may be that during transportation, the bicycle is clamped somewhere, and the cock bent slightly. If you cannot achieve a clear gear change, then remove the cock and put it on the table.
If it is slightly crooked, then you need to bend it. Do not overdo it, aluminum can give microcracks. How exactly to bend it. I will not advise. I do it in a handicraft way. I put it on the bike and pull it with my hands. Ideally, you need to edit with a special typewriter, which even takes into account the asymmetry of the dropouts.
Cycling does not switch gears
Transmission components should be kept in good condition at all times, lubricating the chain promptly, adjusting switches and troubleshooting. As the kilometers increase on the bike, individual parts wear out, and if maintenance is not performed on time, the part may become unusable altogether. In this article, we will look at the most common problem associated with speed derailleurs.
Cables and shirts
This problem most often occurs among novice cyclists. It is enough to click the shifter or even remove the cable from the shirt and inspect it for contamination. In addition, the cable can be unwound somewhere, which will significantly affect the shifting.
How to switch gears correctly?
Correct gear shifting allows you to ride easier and more comfortable with less effort, as well as increase the service life of all elements of the bicycle transmission. We have prepared several rules and recommendations on how to properly switch speeds on a bike:
- You can switch speeds only on the move, that is, while pedaling.
- For correct and smooth shifting when shifting gears, it is necessary to reduce the load on the pedals.
- Switching speeds should occur sequentially, you do not need to jump over several speeds at once.
- When going uphill, you should not throw the chain between the chainrings, but between the rear stars it is quite acceptable. If there is a slide in front, it is better to change the speed before you enter it.
- If, after switching the gears, extraneous sounds are heard, it means that the switching did not occur and it is necessary to squeeze the shifting lever.
If the fault diagnosis and adjustment is carried out correctly, in accordance with the algorithm, it lasts for a long time. Often, in practice, it is limited to setting the rear derailleur. Timely elimination of violations in the system will allow the transmission to serve for a long time without failures. To reduce the wear rate, it is necessary to use the speed system correctly.
Design and principle of operation of the rear cross-over
The rear derailleur design of a bike from Shimano, SRAM or other manufacturers (such as SunRace) is not particularly complex or highly technological. The crossover is a set of the following nodes:
Attaching the switch to the cock. Place with bolt hole. With this assembly, the switch is mounted on the bike (bolted to the cock).
The principle of operation of the rear derailleur is quite simple. When you change the speed limit on the shifter (which is located on the steering wheel), the gear shift cable is pulled or loosened. Since it is rigidly fixed with a fixing bolt to a spring-loaded parallelogram, this causes the latter to shift towards the larger star, when the cable is pulled (with decreasing speed), and to a smaller star, when it is weakened (with increasing speed). When the cable is loosened, the spring provides the parallelogram displacement. Changing its position, he shifts the foot with a guide roller and a tensioner roller in the direction we need. The latter, deflecting back under the influence of the spring, removes the chain slack, which improves the switching accuracy. The guide roller shifts the chain to the desired star, which, clinging to the small protrusions on the sprocket, jumps to it (this is if there is a switch from a smaller star to a larger one, if on the contrary, the chain simply jumps from a larger star to a smaller one).
I would like to note that the movement of the parallelogram occurs not in one plane, but in several, because he needs to compensate for the different diameters of the rear system stars (the chain tensioner serves the same compensation).
It should also be said that this is how most rear derailleurs (except planetary) work, regardless of the manufacturer (Shimano, SRAM) or the number of speeds (6, 7, 8, 9, 10, etc speed systems)
You can clearly see the principle of operation of the rear derailleur in the video.
Internal switching mechanism
City bikes often use an internal gearshift mechanism that is hidden inside the rear planetary hub (for example, the new Forward Surf 2.0 cruiser). Planetary hub bikes have only one chainring and one sprocket. The number of speeds / gears of the planetary bushings is usually from 3 to 7. The planetary hub has a rather complex internal structure.
Pluses of planetary bushings: they withstand adverse weather and road conditions well, since the mechanism and all its parts are enclosed in a case and, as a result, are reliable and durable; you can switch speeds without pedaling.
Cons of planetary bushings:. heavy weight;. very difficult repairs, impossible in field conditions.
Adjusting and adjusting the rear derailleur of the bike
After we have finished the preparatory work, we can proceed to setting up the rear derailleur of the bike. For this we need a minimum of tools and efforts.
Adjusting the front derailleur
- We put the speed switch in the following ratio: the smallest star in the front and the largest in the back;
- We unscrew the cable;
- Using the screw of the limiter for low gears, we adjust the position of the frame, it should be at a distance of no more than 3 millimeters from the chain;
- Stretch the front derailleur cable slightly;
- Switch the speed to the middle sprocket and check if the chain is touching the outer frame. If it touches, it is necessary to tighten the cable more;
- We put the derailleur on the smallest sprocket and check how easy it is to change gears. If the switch does not work, adjust the high gear limiter screw.
the line of the chain is the distance from the plane of symmetry of the frame to the chain / stars.
Front derailleur problems are often caused by an incorrect chain line, that is, the chain is too close or, more often, too far from the bike‘s middle line. This is usually caused by the wrong carriage selection for the system.
Cable holder (rear)
Attaching the end of the cable to the derailleur bolt often causes problems. If it is approached at the wrong angle, the geometry of the parallelogram will be distorted and therefore it will be difficult to achieve normal derailleur movement throughout the gear range. The derailleur usually has a groove or washer with a curved end to indicate that the cable is attached correctly.
For example, on the derailleur pictured above, the cable is not properly attached. You can see the groove between the cable and the bend in the washer.
Front derailleur height adjustment.
The first step to properly setting the front derailleur is to check your altitude. If the holder is too high above the drive sprocket, then it will not shift gears well. If it is too low, then it will not move the chain from star to star at all.
- Shift the derailleur so that the chain is on the middle drive sprocket. In this case, the outer plate of the holder will be directly above the outer star.
- The distance between the teeth of the outer sprocket and the bottom edge of the outer holder plate should be 1. 2 mm. A coin will serve as a tool for measuring the gap, since its thickness is approximately 1.5 mm. The coin should clearly fit into the slot (see photo).
- To change the derailleur height, first release the cable tension by shifting to the smallest drive sprocket. Then loosen the gear selector retaining bolt, adjust the height and retighten the bolt. Switch back to the middle guide sprocket and check the holder height (see photo).
- Repeat this procedure until the distance between the teeth on the outer drive sprocket and the bottom edge of the outer carrier plate is 1 to 2 mm.
Note: The front derailleur clip will usually leave a mark on. by which you can navigate when changing the height.
Front derailleur adjustment
The front derailleur is less common than the rear derailleur. Bicycles with this device are cheaper. The front derailleur moves the chain to the stars of the system. Moving from side to side, he pushes the chain to the next star.
- Switch frame. A chain passes through it, this is the main element when switching speeds. She moves to the sides in front of the leading stars.
- Parallelogram. the mechanism itself (speed switch). Includes spring.
- Fastening to the frame.
- Upper stop L.
- Lower stop H.
- Fastening the cable.
The main problem with the front derailleur is that the chain hits the frame when driving. You can fix this problem yourself.
How To Adjust Gears On A Mountain Bike | Halfords UK
- Jet ski
- Rock climbing
Adjusting the bike‘s front derailleur is done after the mechanism has been re-installed or replaced. This may require a certain tool (curly screwdriver and wrenches with a minimum pitch).
Important! The smaller the clearance between the derailleur frame and the chain, the easier it will be to change gears.
From the instructions above, you can understand how to set up the front derailleur on your bike with your own hands. But you should be aware that the correct setting does not always work the first time. Sometimes only practice will help to achieve the desired result and, perhaps, the process will have to be repeated several times. But you need to do everything so as not to overdo it, because otherwise you will need to repair the front derailleur.
How to Adjust a Front Derailleur
External Shifting on Speed Bike
The outer type belongs to most multi-speed bicycles. It is used on both mountain and city walking models. The mechanism is made up of gear shifters and stars that form a cassette or system. Variable speed with rear and front derailleurs.
This type of gear shifting can be seen on both the Forward Dortmund city bike (7 speeds) and the Forward Agris mountain bike (24 speeds). You can customize this switch yourself by examining the mechanism.
The combined type is a combination of an external and an internal mechanism. It attaches to the bike’s rear wheel hub.
This mechanism is extremely rare, since it has collected all the negative aspects of both external and internal gearshift systems. It is configured only by a professional.
How to change gears on any bike from Merida to ladies
To ride easily and comfortably with less effort, you need to switch gears correctly.
- When you hear extraneous sounds when changing gears, the transmission has not worked. You need to squeeze the lever of the shifter.
- Use the rear derailleur if you want to conquer the top.
- It’s better to change gears before you start climbing higher ground.
- Shift gears on the move and don’t jump over multiple stars at once.
- Release pedal pressure while changing speed. So the switching will be smooth and correct.
Front derailleur indexing adjustment.
- Switch to inner rear sprocket and middle front drive sprocket.
- The gap between the inner plate of the holder and the chain should be as small as possible, but there should be no friction. Spin the bike pedals to make sure that there is no friction in all places during rotation (see photo).
- To reduce the gap, increase the cable tension by rotating the adjusting drum (see photo).
- If the chain rubs against the inner plate of the holder, reduce the tension on the cable by rotating the adjusting drum (see photo).
- If the adjusting drum is unscrewed to the limit, then return the cable tension to its original position. Unscrew the adjusting drum all the way in the opposite direction. Switch to the inner chainring. Loosen the cable tie bolt, pull gently and retighten the bolt. Repeat the cable tension adjustment as described above (see photo).